This invention relates to live conveyors, and more particularly to clutches for zoned or sectionalized live conveyors.
A number of live conveyor systems are known in which the driven element stops rotating when a load placed on it exceeds a predetermined torque limit. The torque limit may be exceeded when the weight of the load unit on the live roller is too high, or when the load unit encounters an obstacle on the conveyor such as another load unit that has stopped moving.
A major disadvantage with such conveyor systems is that the load units are allowed to contact each other before the live roller stops moving. When the load units are fragile or easily damaged, it is highly undesirable to allow them to touch each other.
To prevent the load units from touching each other, a number of sectionalized or zoned conveyors have been created. Typical zoned conveyors have a number of sections or zones, each zone having a sensor and a motor drive clutch apparatus. Each zone also typically has its own belt and its own means for engaging the clutch apparatus. The presence of a load unit in one zone may affect the movement of a load unit in the same or a different zone.
A major disadvantage of the typical prior art zoned conveyors is that they are complicated and expensive, and often contain numerous belts, pulleys, motors, and control units to operate. Typical zoned conveyors also require that the conveyor be specially made or extensively modified to incorporate the zoned drive features. They may not be retrofit onto existing live conveyors.
Although prior art live conveyor clutch assemblies and zone drive systems may disengage the drive means from the live rollers, they do not prevent the roller from rotating if the conveyor is placed in an upward or downward direction. That is, the effect of gravity on the load unit when the conveyor section is at an angle with respect to the horizontal plane may cause the disengaged roller to rotate and the load unit to move, allowing the load unit to strike and damage adjacent load units.
It is therefore desirable to provide an inexpensive zoned live conveyor system that is retrofitable and usable on flat as well as upward and downward applications.